Turbine systems are one example of turbomachines widely utilized in fields such as power generation. For example, a conventional gas turbine system includes a compressor section, a combustor section, and at least one turbine section. The compressor section is configured to compress air as the air flows through the compressor section. The air is then flowed from the compressor section to the combustor section, where it is mixed with fuel and combusted, generating a hot gas flow. The hot gas flow is provided to the turbine section, which utilizes the hot gas flow by extracting energy from it to drive the compressor, an electrical generator, and other various loads.
The combustor sections of turbine systems generally include tubes or ducts for flowing the combusted hot gas therethrough to the turbine section or sections. Recently, combustor sections have been introduced which include ducts that shift the flow of the hot gas, such as by accelerating and turning the hot gas flow. For example, ducts for combustor sections have been introduced that, while flowing the hot gas longitudinally therethrough, additionally shift the flow radially or tangentially such that the flow has various angular components. These designs have various advantages, including eliminating first stage nozzles from the turbine sections. The first stage nozzles were previously provided to shift the hot gas flow, and may not be required due to the design of these ducts. The elimination of first stage nozzles may reduce associated pressure drops and increase the efficiency and power output of the turbine system.
Various design and operating parameters influence the design and operation of combustor sections. For example, higher combustion gas temperatures generally improve the thermodynamic efficiency of the combustor section. However, such increased temperatures require improved cooling of the various turbine system components, in order to prevent or reduce the risk of damage to the components from exposure to high temperatures. However, various problems are associated with known cooling techniques for turbine systems. For example, leakage of cooling air reduces cooling efficiency, and further causes less air to be routed for combustion. Additionally, known designs for cooling various components make inefficient use of the cooling air, causing further inefficiencies. These design and operating parameters are of particular concern when utilizing ducts that shift the flow of the hot gas therein, as discussed above, because of the high temperatures and heat transfer coefficients that are generated in the ducts, and specifically in downstream portions of the ducts.
Accordingly, improved combustor sections for turbomachines, such as for turbine systems, would be desired in the art. In particular, combustor sections with improved cooling designs would be advantageous.